Method and apparatus for applying stress relieving treatment for stranded steel wires

ABSTRACT

A method of applying continuous stress relieving for the stranded steel wires and the likes is provided, wherein the electrical heating power source are properly combined by switching to the stress relieving devices disposed respectively upstream and downstream of a capstan of the system depending on the feeding speed of the stranded wires delivered from the stranding machine thereby applying a uniform and continuous stress relieving to those portions of the stranded steel wires that are stranded and fed during starting and stopping of the stranding machine just in the same manner as with those portions stranded and fed during the usual operation of the machine. Apparatus suitable for effecting such continuous and uniform stress relieving are also disclosed.

United States Patent Nakamura et al.

METHOD AND APPARATUS FOR APPLYING STRESS RELIEVING TREATMENT FORSTRANDED STEEL WIRES Inventors: Kazunori Nakamura; Hiromu Sibasaki, bothof ltami, Japan Assignee: Sumitomo Electric Industries, Ltd.,

Osaka, Japan Filed: June 14, 1974 Appl. No.: 479,384

US. Cl 57/34 R; 57/6; 57/156; 57/166 Int. Cl D071) 3/00 Field of Search57/3, 6, 9, l3, 18, 55, 57/55.5, 34 R, 34 HS, 156, 166

References Cited UNITED STATES PATENTS Peterson et a1. 57/166 X Lucht etal. 57/166 X Primary Examiner-Donald E. Watkins Attorney, Agent, orFirm-Sughrue, Rothwell, Mion, Zinn & Macpeak [57] ABSTRACT A method ofapplying continuous stress relieving for the stranded steel wires andthe likes is provided, wherein the electrical heating power source areproperly combined by switching to the stress relieving devices disposedrespectively upstream and downstream of a capstan of the systemdepending on the feeding speed of the stranded wires delivered from thestranding machine thereby applying a uniform and continuous stressrelieving to those portions of the stranded steel wires that arestranded and fed during starting and stopping of the stranding machinejust in the same manner as with those portions stranded and fed duringthe usual operation of the machine. Apparatus suitable for effectingsuch continuous and uniform stress relieving are also disclosed.

4 Claims, 7 Drawing Figures US Patent Sept. 23,1975 3,906,711

H G ,2 PRIOR ART METHOD AND APPARATUS FOR APPLYING STRESS RELIEVINGTREATMENT FOR STRANDED STEEL WIRES BACKGROUND OF THE INVENTION 1. Fieldof the Invention The present invention relates to a method of applying acontinuous stress relieving (a kind of annealing at lower temperaturethan normal one) for the stranded wire consisting of plurality ofsteelwires and the appae ratus therefor.

2. Description of the Prior Art In manufacturing stranded steel wires bystranding plurality of wires stress relieving treatment has usually beenapplied just after said stranding for removing the residual stressremaining therein in order to stabilize the stranded wire products.

Typical examples of the conventional stress relieving methods and theapparatus therefor are to be described in details in conjunction withthe accompanying drawings.

In one embodiment of the conventional systems shown in FIG. 1A and 1Bstranded wire 2 stranded through a stranding machine 1 is taken up ontoa drum 4 by way of a capstan 3 by a winding device. Then, several suchdrums 4 are transferred the vicinity of a heating furnace, wherebyrespective leading ends of the strand in respective drums 4 are rolledout, passed through the heating furnace or the stress relieving furnace5 in parallel with each other and then taken up onto the respectivedrums 6 by the winding device located at the opposite side. Referencenumeral 9 denotes a cooling device. This system, however, has a defeetthat it requires many numbers of man-hours since the stranding processand the'stress relieving process are provided independently.

Another embodiment of the conventional stress relieving systems isillustrated in FIG. 2 proposed by Bethlehem Co. U.S.A., wherein strandedwire 2 stranded by a stranding machine 1 is passed through a capstan 3at first and, afterwards by way of an accumulator which stores thestranded wire loops, applied with the stress relieving treatment in aheating furnace or a stress relieving furnace 5 and then taken up onto adrum 6 at a lower speed by a winding device. Reference numerals 8, 8'and 9,9 denote air cooling devices and water cooling devices disposedrespectively before and after of said stress relieving furnace 5 forpassing the stranded wire 2 therethrough. In this stress relievingsystem, complete stress relieving cannot be obtained for a. certainportion of the stranded wire when the stranding machine is stopped oroperated only intermittently in the case of effecting the wireconnection operationand the like. For overcoming such defect, anaccumulater is used in this system for pulling back the portion nothaving complete stress relieving and subjecting it to the stressrelieving. This system is, however, still disadvantageous in that itrequires an additional device such as above mentioned accumulaterthereby resulting in a complicated operation as well as having higherapparatus costs.

SUMMARY OF THE INVENTION A principal object of the present invention isto provide a method and apparatus for applying a continuous and uniformstress relieving treatment easily for the stranded wire delivered fromthe stranding machine that strands a plurality of steel wires throughoutits operation, that is, from the starting to the arrival at a ratedspeed, during the operation at a rated speed and till the stoppingthereby eliminating the defects of the prior arts.

Another object of the present invention is to provide amethod andapparatus for applying a uniform stress relieving for the portion of thestranded wire that is fed druing the period from the starting till thearrival at the rated speed in the same way as for those portionsdelivered at the rated speed during normal operation.

A further object of the present invention is to provide a method andapparatus for applying a uniform stress relieving for the portion of thestranded steel wire that is fed from the stranding machine during theperiod from the operation at the rated speed till stopping in the sameway as for those portions delivered at the rated speed during normaloperation.

A. still further object of the present invention is to provide a methodand an apparatus, using the electrical heating source of the samecapacity applying not only to the wire at normal continuous stressrelieving velocity but also at stress relieving velocity from startingto normal velocity, even if the two stress relieving devices weredisposed respectively before and after the capstan.

Further object and advantages of the method and apparatus of the presentinvention will become apparent from the following detailed descriptionif read in connection with the accompanying drawings.

DESCRIPTION OF THE ACCOMPANYING DRAWING FIGS. 1A and 1B are schematicillustrations of a conventional stress relieving system;

FIG. 2 is a schematic illustration of another conventional stressrelieving system;

FIG. 3 is a schematic arrangement of the stress relieving systemaccording to the present invention; and

FIG. 4A to FIG. 4C are circuit diagrams for supplying electrical heatingpower to the stress relieving devices for use with the apparatusaccording to the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS The present invention is to bedescribed in details by way of its illustration embodiments but and inno way is it restricted to the accompany drawings.

The embodiment in FIG. 3, showing a schematic arrangement of acontinuous stress relieving apparatus for the stranded steel wireaccording to the present invention, comprises a stranding machine I,stranded steel wire 2 prepared by stranding, for example, a plurality ofsteel wires by said stranding machine, a capstan 3, a take up drum 6,heating devices 5 and 5' disposed respectively before and after saidcapstan 3, and cooling devices 9 and 9 disposed respectively before andafter said capstan 3, all of said heating and cooling devices being usedfor the stress relieving. For the convenience of the explanation, 'theforegoing heating devices and cooling devices are to be referred to asheating devices or stress relieving devices 5 and 5 taken together.

When the stranding machine 1 shown in the drawing is operated normally,said machine 1 rotates at a rated speed and only the heating device 5disposed before of the capstan 3 is operated to effect the stressrelieving.

The stranded wire 2 applied with the stress relieving is wound severalturns around the capstan 3 and then taken up onto the drum 6 through theheating device 5', which is not yet operated and at normal operation,disposed after the capstan 3.

According to the present invention, the uniform stress relievingtreatment can be effected utilizing the continuous stress relievingapparatus described above throughout the operation of the strandingmachine 1 in the manner as described below.

In the case where the normal operation of the stranding machine isinterrupted temporarily, for the reason such as connection of the wiresand the like, a stop button for the stranding machine is actuated, bywhich the electrical power source for the pre-disposed heating device isalso disconnected. The strands to be stranded are, however, strandedusually up to about 3 5 m length due to the inertia force till themachine completely stops by said disconnection operation of the switch.Thus, the portion stranded by the inertia force and delivered from thestranding machine is wound around the capstan 3 as a so-called adefective portion, that is a portion not applied with stress relieving,When the stranding machine is started again, the machine begins torotate by a DC motor or a pole number changeable AC motor, etc., andthen gradually increases its speed to a predetermined lower operationspeed (about one half of the rated speed for normal operation), whilethe strands are stranded to about the length of 5 6 m. When the speed ofthe stranding machine arrives at said predetermined lower operationspeed, the above mentioned heating devices 5 and 5' disposedrespectively before and after the capstan 3 are operated simultaneouslyto heat the stranded wire 2 to a predetermined temperature of 350 400 C.These heating devices 5 and 5 are, of course, designed to effect theheating at the predetermined temperature corresponding to saidpredetermined low speed operation. With the operation of these preandpost-disposed heating devices, the stress relieving is effected in sucha way that the pre-disposed heating device 5 is used for the stressrelieving of the portion stranded after the predetermined low operationtemperature is reached and the post-disposed heating device 5' is usedfor the stress relieving of the portion stranded by way of the inertiaforce and turned around the capstan while the stranding machine isstopped, as well as for the portion stranded in the period from the timethe stranding machine is re-started till it arrives at the predeterminedlower operation speed. Subsequently, when the portion stranded after there-starting and applied with the stress relieving in the pre-disposedheating device 5 comes to the post-disposed heating device 5', theheating by the post-disposed heating device 5' is stopped, and then theelectric power source for said heating device 5' is combined to thepower source for the predisposed heating device 5, as shown in FIG. 4A,to increase the electrical power thereof so that the electric powersupply may be increased corresponding to the acceleratingcharacteristics of the stranding machine as the latter increases itsspeed to the level for the normal operation.

The circuit shown in FIG. 4A comprises a dynamotor 10 having a requiredcapacity as the electrical power source, a predisposed heating device 5consisting of two independent heating coils 11 and 12 and a postdisposedheating device 5 consisting of one coil 13. By switching a changeoverswitch 14 to the side of the coil 13, the pre-disposed heating device 5is operated only by way of the coil 11 and the post-disposed heatingdevice 5 is operated by way of the coil 13 without using the coil 12.The portion of the stranded wire not applied with the stress relievingand wound around the capstan 3 is applied with the stress relieving byusing the coil 13 of the post-disposed heating device 5'. When theportion of the stranded wire heated by the coil 11, which forms a partof the pre-disposed heating device 5, comes to the post-disposed heatingdevice 5, the changeover switch 14 is switched from the coil 13 to thecoil 12, which forms a part of the pre-disposed heating device 5,thereby supplying electrical power simultaneously to two coils 11 and 12of the predisposed heating device 5 to increase the electrical power ofthe heating device 5.

In the arrangement shown in FIG. 413, only the coil 11 is used in steadof two coils 11 and 12 shown in FIG. 4A, wherein the switch 14 for thecoil 13 of the postdisposed heating device 5 is disconnected when theportion of the stranded steel wire heated in the predisposed heatingdevice 5 comes to the post-disposed heating device 5 and,simultaneously, the outputs from the power source 10 is adjusted to alevel corresponding to that for the predetermined low speed for thestranded steel wire. Thereafter, the electrical power supplied to thecoil 11 is gradually increased as the feeding speed of the strandedsteel wire increases from said predetermined low speed.

The arrangement shown in FIG. 4C comprises two dynamotors 15 and 16having respectively about one half capacity of that of the electricpower source 10 in the embodiment shown in FIG. 4A, one dynamotor 15being connected to the coil 11 of a pre-disposed heating device 5 andthe other dynamotor 16 being selectively connected to either of the coil12 of the predisposed heating device 5 and coil 13 of the postdisposedheating device 5 by way of a changeover switch 14. Initially, coils l1and 13 are operated independently from the separate power sources 15 and16 respectively and then only of the coils 11 and 12 of said predisposedheating device 5 are operated by said two power sources.

Although some voltage fluctuations occur at the time of switching ordisconnecting the switch 14, they can be reduced by the stepwiseincrease or decrease of the voltage. The heating devices disposed beforeand after of the capstan are shown herein as high frequency inductionheating means, but the present invention is not necessarily limited touse such heating means and other heating means can also be used such asthose utilizing Joules heat by way of direct conduction and the like.

According to the present invention, as foregoings, stress relievingdevices are disposed respectively before and after of the capstan andselectively actuated by the automatic switching of the electric heatingpower source having a capacity required for the normal operation, andthe heating outputs of the power source are automatically adjustedcorresponding to the feeding speed of the stranded steel wire, wherebycontinuous and uniform stress relieving can be applied for thoseportions of the stranded steel wire that are delivered in the period ofstarting as well as stopping of the stranding machine just in the sameway as for those portions that are delivered during normal operation ata rated speed. Thus, the present invention can produce stranded steelwire of uniform quality with convenient simple facility, therebyproviding great economical advantages.

While the invention has been described in detail and with reference tospecific embodiments thereof, it will be apparent to one skilled in theart that various changes and modifications can be made therein with outdeparting from the spirit and scope thereof.

Whatis claimed is:

l. A method of continuous stress-relieving of a stranded steel wiresimultaneously with a stranding operation, wherein said stranded steelwire is wound onto a pick-up drum by a capstan positioned intermediate astranding machine and the pickup drum and which pulls the wire from thestranding machine and winds it onto the pick-up drum, said methodcomprising:

stress-relieving the stranded steel wire at stations immediatelyupstream and downstream of the capstan, and

adjusting the heating power of the stress-relieving means at saidstations in accordance with the feeding speed of the wire from thestranding machine.

2. A method of continuous stress-relieving of a stranded steel wiresimultaneously with a stranding operation, as claimed in claim 1,wherein: at the start of the stranding machine, stranding is done at aspeed lower than the rated normal speed and said method furthercomprises: stress-relieving the wire simultaneously at said stationsupstream and downstream of the capstan when a predetermined low speed isreached, so that a portion of the wire which has not been stressrelievedat all is stress-relieved at the station downstream of the capstan, andanother portion which has been stranded after the stranding machinereaches the predetermined low speed is stress-relieved at the stationupstream of the capstan, terminating stressrelieving at the stationdownstream of the capstan when said portion stress-relieved upstream ofthe capstan reaches the downstream stress-relief station, and increasingthe speed of the stranding machine gradually to a rate of speed whilegradually increasing the heating power to the stress-relieving device ordevices to match the acceleration characteristics of the strandingmachine.

3. An apparatus for continuous stress-relieving treatment of a strandedsteel wire, said apparatus compris- 6 ing:

a capstan for leading stranded steel wire out of a stranding machineupstream thereof, and for winding the stranded steel wire onto a drumdownstream thereof,

stress-relieving devices disposed respectively immediately upstream anddownstream of the capstan at operative positions with respect to thesteel wire, each stress-relieving device being composed of a heatingdevice and a cooling device,

an electrical power source for supplying heating power to the heatingdevices of the stress-relieving devices, said heating device disposedupstream of the capstan being divided into two heating sections, and

means for selectively switching the power source from one of saiddivided heating sections of said heating device disposed upstream ofsaid capstan to said heating device disposed downstream of said capstan,and vice versa.

4. An apparatus for applying a continuous stressrelieving treatment to astranded steel wire as claimed in claim 3, further comprising: means forsupplying heating power to one of the two divided heating sections ofthe heating device disposed upstream of the capstan and to the heatingsection of the heating device disposed downstream thereof when the speedof the stranding machine is at a predetermined speed lower than itsrated speed, means for switching the electrical power source from theheating section of said heating device disposed downstream of thecapstan to the other of the divided heating sections of said heatingdevice disposed upstream of the capstan when the portion of the strandedsteel wire given the stress-relieving treatment in said stress-relievingdevice disposed upstream of the capstan arrives at the heating devicedisposed downstream of the capstan, and means for simultaneouslyincreasing the power supply gradually to the heating sections of theheating device disposed upstream of the capstan so as to make theheating power correspond with the accelerating characteristics of thestranding machine as its speed increases from said predetermined lowerspeed to said rated speed.

1. A method of continuous stress-relieving of a stranded steel wiresimultaneously with a stranding operation, wherein said stranded steelwire is wound onto a pick-up drum by a capstan positioned intermediate astranding machine and the pick-up drum and which pulls the wire from thestranding machine and winds it onto the pick-up drum, said methodcomprising: stress-relieving the stranded steel wire at stationsimmediately upstream and downstream of the capstan, and adjusting theheating power of the stress-relieving means at said stations inaccordance witH the feeding speed of the wire from the strandingmachine.
 2. A method of continuous stress-relieving of a stranded steelwire simultaneously with a stranding operation, as claimed in claim 1,wherein: at the start of the stranding machine, stranding is done at aspeed lower than the rated normal speed and said method furthercomprises: stress-relieving the wire simultaneously at said stationsupstream and downstream of the capstan when a predetermined low speed isreached, so that a portion of the wire which has not beenstress-relieved at all is stress-relieved at the station downstream ofthe capstan, and another portion which has been stranded after thestranding machine reaches the predetermined low speed is stress-relievedat the station upstream of the capstan, terminating stress-relieving atthe station downstream of the capstan when said portion stress-relievedupstream of the capstan reaches the downstream stress-relief station,and increasing the speed of the stranding machine gradually to a rate ofspeed while gradually increasing the heating power to thestress-relieving device or devices to match the accelerationcharacteristics of the stranding machine.
 3. An apparatus for continuousstress-relieving treatment of a stranded steel wire, said apparatuscomprising: a capstan for leading stranded steel wire out of a strandingmachine upstream thereof, and for winding the stranded steel wire onto adrum downstream thereof, stress-relieving devices disposed respectivelyimmediately upstream and downstream of the capstan at operativepositions with respect to the steel wire, each stress-relieving devicebeing composed of a heating device and a cooling device, an electricalpower source for supplying heating power to the heating devices of thestress-relieving devices, said heating device disposed upstream of thecapstan being divided into two heating sections, and means forselectively switching the power source from one of said divided heatingsections of said heating device disposed upstream of said capstan tosaid heating device disposed downstream of said capstan, and vice versa.4. An apparatus for applying a continuous stress-relieving treatment toa stranded steel wire as claimed in claim 3, further comprising: meansfor supplying heating power to one of the two divided heating sectionsof the heating device disposed upstream of the capstan and to theheating section of the heating device disposed downstream thereof whenthe speed of the stranding machine is at a predetermined speed lowerthan its rated speed, means for switching the electrical power sourcefrom the heating section of said heating device disposed downstream ofthe capstan to the other of the divided heating sections of said heatingdevice disposed upstream of the capstan when the portion of the strandedsteel wire given the stress-relieving treatment in said stress-relievingdevice disposed upstream of the capstan arrives at the heating devicedisposed downstream of the capstan, and means for simultaneouslyincreasing the power supply gradually to the heating sections of theheating device disposed upstream of the capstan so as to make theheating power correspond with the accelerating characteristics of thestranding machine as its speed increases from said predetermined lowerspeed to said rated speed.